Field of the Invention
The present invention relates to a wafer processing method for processing a wafer having a plurality of devices formed on the front side so as to be separated by a plurality of division lines.
Description of the Related Art
A plurality of devices such as integrated circuits (ICs) and large-scale integrations (LSIs) are formed on the front side of a wafer so as to be separated by a plurality of division lines. The wafer thus having the plural devices on the front side is divided into individual device chips by using a dicing apparatus, for example. The device chips are used in various electric equipment such as mobile phones and personal computers.
In the case that the wafer is divided into the individual device chips by using a cutting blade included in the dicing apparatus, there is a problem such that minute chipping occurs on the periphery of each device chip to cause a reduction in die strength. To cope with this problem, the present applicant has proposed a processing method which can improve the die strength of each device chip, and this processing method has been put to practical use. This processing method includes the steps of entirely covering the front side of a wafer with a resist film, next removing the resist film from the division lines by exposure, and next removing the division lines by plasma etching to thereby divide the wafer into the individual device chips (see Japanese Patent Laid-open No. 2006-114825, for example).